Up to now, Tsubaki Factory have been told that we have this image of being reserved and quiet, but with our major debut on the 22nd of February this year, we'd like to do our best to make this year the year where Tsubaki Factory takes the lead role.

Begining in 2013, Yamagishi began to take part in activites outside of Hello Pro Kenshuusei starting with the Winter 2013 Hello! Project concert tour, where she was a back-dancer for several performances. She then continued participating in every Hello! Project concert tour, as well as Soto Fest and the annual Hinatsuri Festival and Countdown Lives, as a trainee, until mid-2015.

After the conclusion of the winter Hello!Con, she participated in the stage play Nettai Danshi, which ran from February 7th to February 17, 2013, alongside Kaga Kaede.[4] On March 6th, she participated in a fanclub event for newcomers Ichioka Reina and Makino Maria.

That I entered the Kenshuusei and then am going to debut in such short fashion makes me nervous, but when I was chosen, I was also surprised. To think that all of those that have supported me until now will be with me forever makes me happy. In Hello! Project there are a lot of groups with varied personalities, I want us to become a group that can reliably put out our personality for everyone to see.[6]

She owned a miniature dachshund named Annie, whom she had since she was in her first year in elementary school.[10] Annie passed away on March 3, 2016.[11]

Yamagishi was a second year middle school when she initially joined Hello Pro Kenshuusei in June 2012. When she joined Tsubaki Factory in April 2015, she was in her second year of high school. She graduated from high school in March 2017.[12]

The following list are notable friendships Yamagishi Riko has acquired:

She says that everything has gotten easier since she joined the program. She's progressed in singing and dancing and has gotten people below her. She thinks she's probably competent when it comes to rhythm but not so much with pitch. Still, she finds the lessons fun and is glad she joined the program.